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Novel photoresist design based on electrophilic aromatic substitution
Author(s) -
Reck B.,
Allen R. D.,
Twieg R. J.,
Willson C. G.,
Matuszczak S.,
Stover H. D. H.,
Li N. H.,
Fréchet J. M. J.
Publication year - 1989
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760291415
Subject(s) - photoresist , moiety , electrophile , latent image , electrophilic aromatic substitution , carbocation , resist , materials science , electrophilic substitution , substitution reaction , polymer , reagent , polymer chemistry , photochemistry , chemistry , organic chemistry , nanotechnology , image (mathematics) , computer science , layer (electronics) , artificial intelligence , catalysis
A new approach to resist materials that exhibit chemical amplification is based on systems comprised of three structural units at least one of which is polymeric: (a) an aromatic moiety such as poly(4‐hydroxystyrene), Novolac, or other aromatic compounds which are susceptible to electrophilic aromatic substitution; (b) a latent electrophile which may be polyfunctional and, in the case of this study, is a carbocation precursor; (c) a material which generates strong acid upon irradiation. Exposure of a film containing these three structural components affords a latent image of acid dispersed in the polymer matrix. In a subsequent baking step, the photogenerated acid reacts with the latent electrophile releasing a very reactive carbocationic species which becomes bound to the aromatic moiety. As one of the components of the resist is polymeric and multifunctional, the result is a rapid increase in molecular weight due to branching and crosslinking of the chains. In terms of imaging, this process translates into the formation of a negative image of the mask although under some conditions a positive image may also be produced. The system shows a very high sensitivity and can provide high resolution images devoid of distortion due to the absence of swelling during development.